Metaphysics special: Is time an illusion?

We are born, time passes and we die. So time must exist, right? The trouble is, it's tricky to pin down what time actually is

Kevin Tachman/trunkarchive.com, getty

By Richard Webb

WE ARE born. We die. We call the span that separates these events time. Its passage is perhaps the most fundamental feature of our human experience, yet we are incapable of saying exactly what it is. Worse – the laws of physics don’t help. That time exists is undeniable, but the way we experience it makes no sense.

“There’s an old joke about time – it’s nature’s way of keeping everything from happening at once,” says physics Nobel laureate Steven Weinberg of the University of Texas, Austin. To us mortals, time is the passage of the sun and seasons, the progressive wrinkling of our skin as we age – irreversible markers of a present that is moving forwards, and a future that is ineluctably becoming the past. Unlike space, time has a natural order. If A influences B, then B is always later in time. This is the central feature of time as we perceive it: as a flowing entity that orders our lives.

There’s only one problem with this, says David Deutsch of the University of Oxford: it’s nonsensical. We see ourselves as living in a present that marches down an imaginary timeline at a set pace. The imagery implies the existence of some sort of universal ticking time setting the beat against which all else is measured. “But what is that other time?” says Deutsch. We’ve only succeeded in creating a new problem.